John and Tashia Morgridge did their best to stay anonymous for years, while giving around $50 million a year to various causes. Now public philanthropists at the head of the TOSA Foundation, they still keep it pretty low-key. But there’s nothing low-key about their conservation giving, which includes more than $50 million over the years just to The Nature Conservancy.

“Slowly we began to realize that we were the only ones who thought we were anonymous,” Tashia Morgridge said in one interview.

The TOSA Foundation is the philanthropic project of the Morgridges, whose wealth comes from John's run as former chairman of tech company Cisco Systems. With an estimated net worth of about $1 billion, the couple went public in 2010 when they joined the Giving Pledge, and announced plans to spend down the foundation’s trust during their lifetimes.

TOSA’s biggest cause is education, but they’ve steadily given millions to conservation over the years, driven by the couple’s love of nature while growing up in Wisconsin, and John Morgridge’s heavy involvement in environmental giant The Nature Conservancy.

He served as a board member for the green philanthropy favorite from 1998 to 2008, as treasurer, vice chair and ultimately chair, and his devotion to the international nonprofit shows in the foundation’s giving. The Morgridges have donated more than $50 million to the organization, mostly in the form of huge chunks of Cisco stock starting in 2005, but also in cash grants. It’s the second-largest beneficiary of the couple, with Stanford University just ahead.

The Nature Conservancy is the most notable conservation grantee for the funder, but not the only one by a longshot. In fact, depending on the year, Tosa will give millions in grants to various green nonprofits, fairly scattered in terms of geography. For example, the foundation has regularly given to conservation efforts at Squam Lakes and other treasured parts of New Hampshire.

The donors have said that their conservation giving stems from their own enjoyment of the outdoors in life, and that’s represented in their giving. Aside from the focus on lake getaways, they’ve given to the Appalachian Trail Conservancy, the Bay Area Ridge Trail, the Pacific Crest Trail Association, as well as Rails-to-Trails.

The foundation is based in the Bay Area, but the Morgridges are originally from Wisconsin and seem to spend time in New Hampshire, so there’s some focus in these regions, but it’s pretty tough to pin their interests down geographically. They’ve also given in Montana and Colorado.

The couple still tries to stay pretty far off the radar, so as far as getting the attention of the TOSA Foundation, there’s no public avenue for applying. But it’s run entirely by the couple, with Tashia Morgridge at the helm.